It could be anything from the crappy plugs at the back, broken signal cable to faulty driver.

Be patient inquisitive and buy yourself a multi meter to check continuity.

1. Open the box and ensure all connections are connected right. Especially DIR and STEP signals to the drive
2. Ensure all is soldered well and plugs especially
3. Swap cables and make sure that the cable is OK. Check motor and the cable to motor connection.
4. read particular motor driver documentation and see if some adjustment there is not wrong.

Anyway, if are persistent you will find the problem and demonstrate it to them. So no need of sending anything back.

There are not so many things that could go wrong, so just take your time. Its board, cable to drive, drive, cable to motor. Thats it. One of these is wrong.


And yes, buying Chinese boards and searching support from the original maker does not make sense. Buy a board from him and then seek help there :-)